Drawing aid assembly

Abstract

A drawing aid assembly includes a tracing screen, a light generating assembly, a controller, a storage area, and a selector. The light generating assembly is arranged to cause a light spot to impinge upon a first side of the tracing screen and the light spot is transmitted to a second side of the tracing screen such that the position of the light spot may be recorded by a user. The controller controls the light generating assembly such that the light spot is arranged to impinge at a number of predetermined positions upon the tracing screen in accordance with a figure to be traced. The storage area retains data defining a number of figures, the storage area being accessible by the controller. The selector enables the user to select a figure to be traced from the number of figures within the storage area.

What is claimed is:  
     
         1 . A drawing aid assembly comprising: 
 a tracing screen;    a light generating assembly arranged to cause a light spot to impinge upon a first side of the tracing screen wherein the light spot is transmitted to a second side of the tracing screen;    a controller for causing the light generating assembly to produce the light spot at predetermined positions on the tracing screen in accordance with a figure to be traced;    a storage area for retaining data defining a number of figures, wherein the storage area is accessible by the controller; and    a selector for selecting a figure to be traced from the number of figures within the storage area.    
     
     
         2 . An assembly according to  claim 1 , wherein the selector comprises an input device for operation by a user in order to provide instructions to the controller.  
     
     
         3 . An assembly according to  claim 2 , wherein the tracing screen is marked at two or more positions, each position corresponding to a controller instruction, wherein in use, the marked positions are used in accordance with light generating assembly to enable the user to select a particular controller instruction.  
     
     
         4 . An assembly according to  claim 3 , wherein the marked positions are formed from surface relief within the tracing screen.  
     
     
         5 . An assembly according to  claim 1 , wherein the selector is connected to the controller.  
     
     
         6 . An assembly according to  claim 2 , wherein the selector is connected to the controller.  
     
     
         7 . An assembly according to  claim 1 , wherein the light generating assembly comprises a movable light source.  
     
     
         8 . An assembly according to  claim 7 , further comprising a drive mechanism for moving the movable light source.  
     
     
         9 . An assembly according to  claim 8 , wherein the drive mechanism is arranged to move the light source along two independent axes within a plane.  
     
     
         10 . An assembly according to  claim 9 , wherein the drive mechanism further comprises a holder containing the light source, the holder being slidably mounted upon two rods, wherein each rod is driven along one of the corresponding axes.  
     
     
         11 . An assembly according to  claim 8 , wherein the drive mechanism comprises a wire and a pulley device driven by a motor.  
     
     
         12 . An assembly according to  claim 1 , further comprising a monitoring device for monitoring the position of the light spot.  
     
     
         13 . An assembly according to  claim 12 , wherein the monitoring device comprises an optical detector and a strip encoder.  
     
     
         14 . An assembly according to  claim 9 , further comprising a monitoring device for monitoring the position of the light spot.  
     
     
         15 . An assembly according to  claim 14 , wherein the monitoring device is provided to monitor the position of the light spot with respect to each axis.  
     
     
         16 . An assembly according to  claim 15 , wherein the monitoring device comprises an optical detector and a strip encoder.  
     
     
         17 . An assembly according to  claim 1 , further comprising a datum monitor adapted to produce a signal when the light spot is located at a predefined position.  
     
     
         18 . An assembly according to  claim 1 , further comprising an attachment device arranged to hold a recording medium adjacent to the tracing screen such that the user may trace the figure by marking the positions of the light spot upon the recording medium.  
     
     
         19 . A method of aiding drawing comprising: 
 selecting a figure using a selector of a drawing aid assembly having a tracing screen including a first surface and a second surface;    positioning a recording medium adjacent to the second surface;    operating the drawing aid assembly including transmitting a light spot through the tracing screen and the recording medium at a number of positions on the tracing screen in accordance with the selected figure; and    marking the positions upon the recording medium such that the selected figure is reproduced.    
     
     
         20 . A method according to  claim 19 , wherein the light spot is positioned at the number of positions sequentially.  
     
     
         21 . A method according to  claim 20 , wherein the light spot is not illuminated during movement between positions.  
     
     
         22 . A method according to  claim 21 , wherein a maximum of one light spot impinges upon the tracing screen at any one time.  
     
     
         23 . A method according to  claim 22 , wherein the figure to be traced is selected by the user.  
     
     
         24 . A method according to  claim 23 , wherein the user selects the figure to be traced by moving the light spot beneath the marked position corresponding to that figure.  
     
     
         25 . A method according to  22 , wherein the figure to be traced is selected by a controller within the drawing aid assembly.  
     
     
         26 . A method of aiding drawing comprising: 
 receiving a selection of a figure from among a stored set of figures;    transmitting a light spot to an exposed side of a tracing screen of a drawing aid assembly at positions on the exposed side of the tracing screen in accordance with received figure selection; and    receiving a marking upon a recording medium positioned above the exposed side to reproduce the selected figure on the recording medium.